The present invention relates to a condenser used in a refrigeration cycle which constitutes, for example, a car air conditioner.
Herein and in the appended claims, the upper side, lower side, left-hand side, and right-hand side of FIGS. 1 and 2 will be referred to as “upper,” “lower,” “left,” and “right,” respectively.
Also, herein, the term “liquid-phase refrigerant” encompasses liquid-phase predominant mixed-phase refrigerant containing a small amount of gas-phase refrigerant.
There has been known a condenser of a refrigeration cycle which constitutes a car air conditioner (see Japanese Patent No. 4743802). The known condenser includes a condensation section, a super-cooling section provided above the condensation section, and a liquid receiver provided between the condensation section and the super-cooling section. Each of the condensation section and the super-cooling section has one heat exchange path formed by a plurality of heat exchange tubes disposed parallel to one another such that their longitudinal direction coincides with the left-right direction and they are spaced from one another in the vertical direction. Refrigerant flowing out of the condensation section flows into the super-cooling section through the liquid receiver. The liquid receiver has a refrigerant inlet which is located at the vertically central portion of the condensation heat exchange path of the condensation section and through which the refrigerant from the heat exchange path flows into the liquid receiver, and a refrigerant outlet which is located above the refrigerant inlet and through which the refrigerant flows out to the super-cooling heat exchange path of the super-cooling section. A partition member (horizontal plate) is disposed in the liquid receiver at a vertical position between the condensation section and the super-cooling section so as to divide the interior space of the liquid receiver into a first space communicating with the condensation section through the refrigerant inlet, and a second space located above the first space and communicating with the super-cooling section through the refrigerant outlet. A suction pipe which is open at upper and lower ends thereof and establishes communication between the first space and the second space is disposed in the first space of the liquid receiver. The interior space of the suction pipe communicates with the second space through a communication opening in the form of a through hole provided in the partition member.
In the condenser described in the above-described publication, the refrigerant having passed through the condensation section flows into the first space within the liquid receive though the refrigerant inlet, and is separated into gas-phase refrigerant and liquid-phase refrigerant. The liquid-phase refrigerant flows into the second space through the suction pipe, and then flows into the super-cooling section through the refrigerant outlet.
However, the condenser described in the above-described publication has the following problem. Since the refrigerant inlet is located at the vertically central portion of the condensation heat exchange path of the condensation section, during operation of a car air conditioner, liquefaction of refrigerant proceeds and liquid-phase refrigerant stagnates in at least some of the heat exchange tubes of the condensation section heat exchange path, which heat exchange tubes are located below the refrigerant inlet. As a result, it becomes impossible to effectively utilize the entire condensation section for heat exchange, and condensation efficiency deteriorates. Further, since a large amount of working oil for a compressor of the car air conditioner (hereinafter referred to as “compressor oil”) mixes into the liquid-phase refrigerant stagnating in the condensation section, the circulation of the compressor oil becomes poor.
An effective measure for solving such a problem is to shift the position of the refrigerant inlet to a lower position. However, in such a case, most of the gas-phase refrigerant which is a portion of the gas-liquid mixed-phase refrigerant having flowed from the condensation section into the first space of the liquid receiver through the refrigerant inlet enters the suction pipe along with the liquid-phase refrigerant. As a result, the gas-liquid separation effect at the first space within the liquid receiver is impaired.